Requirements Engineering

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Transcript of Requirements Engineering

True StoriesAriane 4Ariane 5Very successful rocket.Since its first flight in 1988 until the last, in 2003, it made 113 successful launchesAriane 5's first flight on 4 June 1996 failed with the rocket self-destructing 37 seconds after launch because of a malfunction in the control software.Sorry, it was a conversion from 64-bit floating point to 16-bit integer that overflowed.I should have avoided that error.ArianeMars OrbiterThe spacecraft was launched on December 1998.

It disintegrated on September 1999 while entering the Athmosphere of Mars.Berlin AirportStart Project,Will be finished on October 20112006Lauro Canonica , 11 9 2015Requirements EngineeringAriane 5 Failure Investigation ReportThe software of Ariane 4 was reused for Ariane 5.

Ariane 5 acceleration was bigger than the previous model and one algorithm failed returning an Integer conversion error.

The automatic controls of Ariane 5 decided for self destructionTESTERSorry, we reused the previous testsand we missed checking withthe new acceleration.REQUIREMENTSSorry, The faulty algorithm was needed only in Ariane 4. If we removed the old requirement, we would have saved Ariane 5.Mars Climate OrbiterMars Climate Orbiter Failure Investigation ReportThere were two main contractors:- LockHeed Martin Aeronautics- Jet Propulsion Laboratory

The two companies didn't work in the same measuring system.

The Orbiter miscalculated its position as metric values wereexpected but imperial values were delivered.LockHeed Martin AeronauticsJet Propulsion LaboratorySorry, I didn't correctly read the requirement about the measuring unitsSorry, integration testing was not done correctly.ArianeMars OrbiterBerlin AirportArianeMars OrbiterBerlin AirportSorry, I should have checked if all the requirements were tested and implemented.A simple check would have saved the Orbiter.We are a little late,it will be ready in June 2012Oct2011Small issues,it will be ready in March 2013Jun2012Uh oh, ahem, it will be ready in 2014Mar2013Sorry,We have no idea,sometime after 2016 !Jan2014Poor change Management

Continuous changes and new requirements. 500 in the last 3 years.Cabling chaos

The requirements for cabling were wrong. The space reserved for the wires is too small and it is planned for incompatible cable types.Excessive complexity of the fire safety system

For esthetic reasons, the smoke has to be pushed away with pipes below the floor instead of above the ceiling.This requirement goes against the natural behavior of smoke and increases the complexity enormously.Bad management of requirements

DEVELOPERTESTERREQUIREMENTSDEVELOPERRequirements Engineeringis the base for successful projects.Berlin Brandenburg Airport (BER)The main escalators for the basement are too short. The ceiling height changed and the requirement was not updated.Requirements Engineering = Figure out what you want to do and let other people know about itThank youforYour attention